Validity of autorefraction after cataract surgery with multifocal ReZoom intraocular lens implantation

A retinal simulation study on the influence of spherical aberration, astigmatism and optotype on the Jackson cross cylinder test

PURPOSE

To study how spherical High-Order Aberration (HOA), astigmatism levels (-0.75 D and -1.25 D), and optotype type (dot pattern vs. letter row) influence patients' responses in identifying the cylinder axis orientation with the Jackson Cross Cylinder Technique (JCCT).

METHODS

Numerical simulations of retinal images corresponding to JCCT procedures were conducted and evaluated by 40 subjects. In order to do this, synthetic aberrometric profiles with and without HOAs (4th-order and 6th-order spherical aberrations) and two different astigmatism levels were generated from different Jackson Cross Cylinder axis positions and flips. The variable under study was the percentage of correct responses (hits) during each flip of the cross-cylinder lens. Statistical significance was assessed through confidence intervals overlapping evaluation.

RESULTS

To achieve 90 % accuracy, the JCCT should begin by deviating >7.5° from the subject's astigmatism axis without spherical HOA and by >15° with them. The magnitude of astigmatism had minor relevance. The dot pattern was more accurate than the letters without HOAs; however, 72.5 % of observers considered that letter optotypes simplify the blur discrimination task.

CONCLUSIONS

According to our simulation experiment for astigmatic axis selection with JCCT, the presence of spherical HOAs significantly impacts the accuracy of patient responses. The type of optotype and the magnitude of astigmatism did not exhibit a clear relationship with accuracy, except in the case of the dot pattern optotype in the absence of HOAs. Under these conditions, the dot pattern achieved the highest rate of accurate responses.

Refractive outcomes of immediately sequential bilateral cataract surgery in eyes with long and short axial lengths

PURPOSE

To report the refractive outcomes of long (≥25.00 mm) and short (≤22.00 mm) axial length (AL) eyes undergoing immediately sequential bilateral cataract surgery (ISBCS).

METHODS

In this retrospective cohort study, patients who underwent ISBCS were identified and eyes of patients with bilateral long and short ALs were included. Pre- and postoperative biometry, autorefraction, and ocular comorbidities or complications were recorded. The primary outcome was the mean refractive prediction error.

RESULTS

Thirty-seven patients (74 eyes) with long ALs and 18 patients (36 eyes) with short ALs were included. The means ± standard deviations of the ALs were 26.40 ± 1.38 mm and 21.44 ± 0.46 mm in the long and short AL groups, respectively. In long AL eyes, the mean absolute error from the biometry-predicted refraction was - 0.16 ± 0.46 D, corresponding to 74% of eyes achieving a refraction within ±0.50 D of the predicted value. In short AL eyes, the mean absolute error was - 0.63 ± 0.73 D, corresponding to 44% of eyes achieving a refraction within ±0.50 D of the predicted value. Eight (44.4%) patients with short AL eyes had a myopic deviation greater than ±0.50 D from the predicted result in both eyes.

CONCLUSIONS

Compared to patients with long AL eyes, ISBCS in patients with short ALs had a wider variance in refractive outcome and a lower rate of achieving a postoperative refraction within ±0.50 D of the predicted target.

Influence of isofocal intraocular lenses on objective refraction based on autorefraction and aberrometry

PURPOSE

To evaluate and compare the objective refractions obtained by autorefraction and aberrometry under different lighting conditions with an isofocal intraocular lens (Isopure, BVI medical, Liége, Belgium) compared to a monofocal control lens (Micropure, BVI medical, Liége, Belgium) with the same platform and material.

METHODS

Prospective, comparative and randomized study on patients undergoing cataract surgery and bilateral isofocal or monofocal IOL implantation. A total of 44 subjects were randomly assigned to either the isofocal group (n = 22) or the Micropure (n = 22). Manifest refraction (MR) was always performed under the same lighting conditions for all the patients. For objective refraction the autorefractor KR8800 and the aberrometer OPD-Scan III (Nidek Inc., Tokyo, Japan.) were used. For each eye included in the study, six result sets were collected: MR, AR (autorefraction measured with the autorefractor), WF-P and WF-M (Zernike-coefficients-based objective refraction, photopic and mesopic pupil size), OPD-C and OPD-M (autorefraction measured with the aberrometer in photopic and mesopic conditions).

RESULTS

The mean sphere for MR was 0.03 ± 0.32D for the Isopure group and 0.24 ± 0.22D for the monofocal group (p = 0.013). For the Isopure group, Friedman analysis showed statistically significant differences for sphere measured with WF-P (p = 0.035), WF-M (p = 0.018) and OPD-M (p = 0.000), and SE measured with OPD-M (p = 0.004). In the Micropure lens group, the Friedman analysis showed differences for all values studied (p < 0.05). Correlation coefficients showed that AR is the objective method with the strongest correlation values for all components of refraction for both groups.

CONCLUSION

The modification of the surfaces of the isofocal lens does not have a negative impact on the refraction obtained by AR compared to a standard monofocal intraocular lens.

Refraction and defocus curves in eyes with monofocal and multifocal intraocular lenses

Several clinical techniques have been described to evaluate visual performance and optical quality with intraocular lenses (IOL). However, subjective refraction remains one of the most important methods for assessing post-surgery results, taking decisions about retreatments, advanced spectacle prescription and the refinement of the constant for the formula used in the IOL power calculation. Beyond clinical refraction, defocus curve measurement has been described as a complementary tool for assessing visual performance and taking clinical decisions. However, to date, there are no clinical guidelines or evidence-based protocols published in the scientific literature recommended for pseudophakic patients implanted with either monofocal or multifocal IOLs. This narrative review highlights the importance of clinical refraction in pseudophakic eyes, its utility in the decision of different types of IOL implantation, and describes a clinical refraction protocol for eyes implanted with monofocal and multifocal IOLs.

Automated and subjective refraction with monofocal, multifocal, and EDOF intraocular lenses: review

Automated refraction (Scheiner principle) is universally used to start a visual examination. Although the results are reliable in eyes implanted with monofocal intraocular lenses (IOLs), they may be less precise with multifocal (mIOL) or extended depth-of-focus (EDOF) IOLs and can even indicate a refractive error that does not clinically exist. Autorefractor results with monofocal, multifocal, and EDOF IOLs were investigated through literature search analyzing the papers reporting the difference between automated and clinical refraction. The average difference ranged between -0.50 diopter (D) and -1.00 D with most mIOL and EDOF IOLs. The differences in astigmatism were generally much lower. Autorefractors using infrared light cannot measure eyes with high technology IOLs precisely because of the influence of the refractive or of the diffractive near add. The systematic error induced with some IOLs should be mentioned in the IOL label to prevent possible inappropriate refractive procedures to treat apparent myopia.

Patient reported outcomes after implementation of an enhanced depth of focus intraocular lens with low postoperative myopia

Background

Enhanced depth-of- focus intraocular lenses (EDOF IOL) have filled the gap between monofocal and multifocal intraocular implants with optical qualities of monofocal lenses and usually minor dysphotopsias typical for multifocal lenses. The purpose of this study was to evaluate visual outcomes after bilateral implantation of a new EDOF IOL in patients with requirements for perfect near and intermediate vision.

Methods

The study included 15 patients (29 eyes as one was amblyopic) with bilateral implantation of LUXSMART EDOF IOL (Bausch & Lomb) with a targeted myopia (between -0.25 and -0.50D) in both eyes. Monocular corrected and uncorrected visual acuity for far, intermediate and near as well as refractive outcomes were evaluated at 1, 3, 6 and 12 months after the surgery. Additionally, binocular visual acuity, contrast sensitivity and defocus curve were measured at the final follow-up visit. At 12 months' visit patients completed a questionnaire evaluating patient satisfaction, spectacle independence and presence of dysphotopsias.

Results

Binocular uncorrected visual acuities at 12 month's visit were 0.13 ​± ​0.16, 0.06 ​± ​0.08, 0.07 ​± ​0.09 and 0.15 ​± ​0.09 logMAR for far distance, 80 ​cm, 66 ​cm and 40 ​cm respectively. Corrected binocular visual acuities at 12 months were 0.00 ​± ​0.00, 0.05 ​± ​0.07, 0.05 ​± ​0.06, 0.13 ​± ​0.16 respectively for distance, 80 ​cm, 66 ​cm and 40 ​cm. Automated refraction spherical equivalent at 12 months' visit stood at -0.70 ​± ​0.48D, which was 0.46D less than calculated biometric target, however spherical equivalent of subjective refraction at 12 months equaled -0.49 ​± ​0.46D, which was closer to preoperative biometric target. Defocus curve had gentle shape without peaks typical for monofocal IOLs. Binocular contrast sensitivity results were superior to average results for that age group and equaled 1.78 ​± ​0.16 logMAR without correction and 1.81 ​± ​0.13 logMAR with correction. Spectacle independence for near and intermediate distances was achieved in all patients and for far distance in 73.3% of patients. Burdensome dysphotopsias were not reported in any case.

Conclusions

EDOF IOLs targeted bilaterally at low myopia can provide excellent near and intermediate visual acuity and independence of any optical correction in majority of cases. This approach can be used in selected patients who are focused on stationary activities.

Autorefraction as an Objective Method to Evaluate Accuracy of Intraocular Lens Calculation Formulas

PURPOSE

To compare the spherical equivalent (SE) and astigmatic prediction error between subjective refraction (SUBref) and autorefraction (AUTOref) after cataract surgery to determine whether the latter is useful as an objective method to compare the accuracy of different methods of intraocular lens (IOL) power calculation.

METHODS

Postoperative refraction was examined using two techniques: SUBref and AUTOref. The results of these two techniques were compared. Predicted postoperative refraction for spherical outcome was calculated with the Barrett Universal II (BUII), Haigis, Holladay I, SRK/T, Hoffer Q, and BUII with measured posterior corneal astigmatism (MPCA) formulas. Predicted postoperative refraction for astigmatic outcome was calculated with the Barrett Toric calculator, vergence-based toric calculator using the Holladay 1 formula for effective lens position, and Barrett Toric calculator MPCA formulas. Formula accuracy and ranking were compared between the two methods of refraction.

RESULTS

Data were obtained from 219 eyes of 155 patients. Statistically significant differences were detected between SUBref and AUTOref for SE, J₀, and J₄₅ (P < .001). The spherical outcome formula analysis demonstrated no significant differences, whereas the predicted cylinder power analysis demonstrated significant differences within individual formulas between SUBref and AUTOref measures. The lowest median absolute error and the highest percentage of eyes achieving their refractive target for both SUBref and AUTOref were achieved with the BUII formula and the Barrett Toric calculator.

CONCLUSIONS

AUTOref is a useful method with adequate accuracy to determine spherical and astigmatic outcome and equally or more effective in being able to discriminate between spherical outcome formulas. The AUTOref method can allow valuable studies to be conducted in less-than-optimal environments and provides the ability to compare studies without the confounding factors of SUBref. [J Refract Surg. 2022;38(9):580-586.].

Subjective and objective refractions in eyes with extended-depth-of-focus intraocular lenses using echelette optics: clinical and experimental study

PURPOSE

To evaluate differences in subjective and objective refractions in eyes with extended-depth-of-focus intraocular lenses (EDOF IOLs) using echelette optics, and the effect of the light wavelength used during examinations.

METHODS

In the prospective study, subjective and objective refractions of 128 eyes of 64 patients were examined 3 months after implantation of the EDOF IOLs (ZXR00V, Johnson & Johnson Surgival Vision). Objective refractions were measured using an autorefractor with a near-infrared (NIR) light source. Clinical differences in the spherical, cylindrical and spherical equivalent (SE) refractions between the subjective and objective refractions were evaluated. Then, lens powers of monofocal, EDOF and diffractive bifocal IOLs in the use of a 850-nm light source were measured experimentally for using a lensmeter, and the differences from the monofocal IOLs were calculated.

RESULTS

The mean objective refractions were more myopic (p < 0.001) than the subjective refractions; the differences in the spherical, cylindrical and SE refractions were -0.71, -0.26 and -0.84 dioptre, respectively. Experimental investigation resulted that there was the mean difference of 0.83 D with the EDOF from monofocal IOLs at 850 nm, while the difference was -0.20 D with bifocal IOLs.

CONCLUSIONS

The diffractive EDOF IOLs using echelette gratings inherently induced constant differences in the subjective and objective refractions, which arose from the chromatic difference in IOL powers for the visible and NIR lights.

Agreement and variability of subjective refraction, autorefraction, and wavefront aberrometry in pseudophakic patients

PURPOSE

To evaluate the comparability and variability of subjective refraction (SR), autorefraction (AR), and wavefront aberrometry (WA) in pseudophakic patients.

SETTING

Hanusch Hospital, Vienna, Austria.

DESIGN

Prospective study.

METHODS

Subjective refraction was performed by 2 independent examiners at 2 study visits. Furthermore, 5 measurements of AR and WA were performed in each patient at both visits. Agreement between the 3 refraction methods for spherical equivalent (M) and cylindrical vectors (J0, J45) was analyzed using Friedman multiple comparison and Bland-Altman plots. Predictability of spherical equivalent determined by SR from AR and WA measurements was tested with partial least squares regression and random forest regression.

RESULTS

Ninety eyes of 90 pseudophakic patients were measured. The mean absolute error and arithmetic mean difference of SR measurements of M, J0, and J45 were comparable between both examiners. A small mean difference was found for SR between both visits. Spherical equivalent was more negative when measured by AR [-0.87 diopters (D)] and WA (-0.90 D) compared with SR (-0.60 D), whereas astigmatic vectors agreed well. Good test-retest reliability was found between all 3 refraction methods for M, J0, and J45. Partial least squares regression and random forest regression showed moderate predictive power for M measured by objective refraction and SR.

CONCLUSIONS

Reproducibility and reliability of SR measurements in pseudophakic patients showed good agreement. AR and WA measured the spherical equivalent more myopic than SR, whereas astigmatic vectors were comparable between the 3 methods after uneventful cataract surgery.

Impact of Lens Material on Objective Refraction in Eyes with Trifocal Diffractive Intraocular Lenses

Purpose: Compare subjective (Rx) and objective (ObjRx) refractions outcomes with two autorefractors models and an aberrometer in eyes implanted with a hydrophobic trifocal IOL (FineVision POD F GF, Physiol, Liége, Belgium) and a hydrophilic one (FineVision POD F, Physiol, Liége, Belgium).Methods: Prospective comparative cohort study, with 100 subjects randomly assigned to either the POD F group (n = 50) or the POD F-GF group (n = 50). Postoperative eye examinations at 1-month visit included seven result sets, one for each assessment method: Rx, AR (automated refraction measured with the autorefractor KR8800), WF-P (Zernike-coefficients-based objective refraction, photopic pupil size), WF-M (Zernike-coefficients-based objective refraction, mesopic pupil size), WF-4 (Zernike-coefficients-based objective refraction, 4 mm pupil), OPD-C (automated refraction measured with the aberrometer OPD in the central pupil/photopic conditions), and OPD-M (automated refraction measured with the aberrometer OPD under mesopic conditions).Results: Mean differences between ObjRx and Rx reached statistical significance for sphere and spherical equivalent (M) only with OPD-C in the POD F-GF group. All ObjRx methods showed significant differences with Rx in the POD F group, with some values differing by more than 0.50 D (-0.58 D in M for the WF-P). Bland Altman plots showed better agreement for the astigmatic components, and for sphere and spherical equivalents in both IOL groups measured with AR and OPD-M.Conclusions: None of the objective methods of refraction evaluated in this study were as reliable as the subjective refraction, irrespective of the lens material, but POD F-GF ObjRx seems to differ less with Rx than POD F ObjRx values.

V. SD, Nagaraj S, Wittberg DM, Stamper RL, Keenan JD. Accuracy of autorefraction in an adult Indian population

Purpose

Autorefractors allow non-specialists to quickly assess refractive error, and thus could be a useful component of large-scale vision screening programs. In order to better characterize the role of autorefraction for public health outreach programs in resource-limited settings, the diagnostic accuracy of two autorefractors was assessed relative to subjective refraction in an adult Indian population.

Methods

An optometrist refracted a series of patients aged ≥50 years at an eye clinic in Bangalore, India using the Nidek ARK-900 autorefractor first, followed by the 3nethra Royal autorefractor, and then subjective refraction. The diagnostic accuracy of each autorefractor for myopia, hyperopia, and astigmatism was assessed using subjective refraction as the reference standard, and measures of agreement between refractions were calculated.

Results

A total of 197 eyes in 104 individuals (mean age 63 ± 8 years, 52% female) were evaluated. Both autorefractors produced spherical equivalent estimates that were on average more hyperopic than subjective refraction, with a measurement bias of +0.16 D (95%CI +0.09 to +0.23D) for Nidek and +0.42 D (95%CI +0.28 to +0.54D) for 3nethra. When comparing pairs of measurements from autorefraction and subjective refraction, the limits of agreement were approximately ±1D for the Nidek autorefractor and ±1.75D for the 3Nethra autorefractor. The sensitivity and specificity of detecting ≥1 diopter of myopia were 94.6% (95%CI 86.8–100%) and 92.5% (95%CI 88.9–97.5%) for the Nidek, and 89.2% (95%CI 66.7–97.4) and 77.5% (95%CI 71.2–99.4%) for the 3Nethra. The accuracy of each autorefractor increased at greater levels of refractive error.

Conclusions

The sensitivity and specificity of the Nidek autorefractor for diagnosing refractive error among adults ≥50 years in an urban Indian clinic was sufficient for screening for visually significant refractive errors, although the relatively wide limits of agreement suggest that subjective refinement of the eyeglasses prescription would still be necessary.

Automated refraction after trifocal and trifocal toric intraocular lens implantation

BACKGROUND

To analyze the correlation between automated refraction and manifest refraction after implantation of a trifocal intraocular lens or its toric version.

METHODS

This cross-sectional study involved 105 eyes of 105 patients. Subjects were divided in two groups: 62 with trifocal (AcrySof PanOptix) and 43 with trifocal toric (AcrySof PanOptix Toric) intraocular lenses. Automated refraction was employed as starting point for obtaining the manifest refraction. Automated refraction and manifest refraction measurements were analyzed and compared using the vector analysis 3 months after the surgery.

RESULTS

In both groups, the higher differences between automated refraction and manifest refraction measurements were found for the cylinder and the spherical equivalent (M). Cylinder values for PanOptix were: -0.60 ± 0.36 D with automated refraction and -0.17 ± 38 D with manifest refraction (p < 0.001); for PanOptix Toric, the values were: -0.49 ± 0.31 D with automated refraction and -0.05 ± 0.21 D with manifest refraction (p < 0.001). M values for PanOptix were: -0.23 ± 0.31 D with automated refraction and -0.03 ± 0.16 D with manifest refraction (p < 0.001); for PanOptix Toric, the values were: -0.13 ± 0.40 D with automated refraction and 0.01 ± 0.12 D with manifest refraction (p < 0.001). For the PanOptix group, intraclass correlation coefficients were: 0.51 (sphere), 0.64 (cylinder), 0.42 (M), 0.62 (J0), and 0.37 (J45). For the PanOptix Toric group, the intraclass correlation coefficients were: 0.39 (sphere), 0.61 (cylinder), 0.39 (M), 0.53 (J0), and 0.09 (J45).

CONCLUSION

The results of this study suggest that patients implanted with the trifocal and the trifocal toric intraocular lens under study showed similar automated refraction results between them, with a slight trend to more negative amounts of cylinder and M. Nevertheless, clinicians should carefully confirm all parameters of the refraction with manifest refraction.

Accuracy of a Smartphone-based Autorefractor Compared with Criterion-standard Refraction

SIGNIFICANCE

Uncorrected refractive error is a prevalent problem throughout the world especially among the low-income population who have limited access to professional eye care and cannot afford eyeglasses.

PURPOSE

The purpose of this study was to evaluate the accuracy and usability of a low-cost, portable, smartphone-based autorefractor (Netra, EyeNetra Inc., Somerville, MA) in adults.

METHODS

A cross-sectional study was conducted to compare the portable refractor with subjective (manifest and cycloplegic) refraction for sequential adult participants with best-corrected visual acuity of 20/40 or greater. For each method of refraction, the spherical equivalent was calculated. Differences between methods were tested with linear mixed regression models. A validated usability questionnaire was administered regarding ease of use (100-point scale, higher scores better) for the portable autorefractor.

RESULTS

Eighty-seven subjects (152 eyes) were studied (age range, 20 to 90 years; mean ± standard deviation, 51.9 ± 18.3 years). Mean spherical equivalent by the portable device was -2.76 D (range, -14.75 to 3.63 D) compared with -2.49 D (range, -15.25 to 4.25 D) by manifest refraction. The mean relative difference in spherical equivalent between methods was -0.27 D (P = .001, significantly different than 0 D). The mean absolute difference between methods was 0.69 D (P < .001, significantly different than 0.5-D absolute difference). Similar results were found when comparing spherical equivalent between Netra and cycloplegic refraction methods. Subjects reported average ease of use for the Netra of 75.4 ± 19.8.

CONCLUSIONS

The portable autorefractor had small but clinically significant differences from subjective refraction. The device's scores on the usability scale indicate good overall patient acceptance. The device may be valuable for use where there is limited access to a trained refractionist.

Visual Performance after a Unilateral or Bilateral Implantation of Enlarged Depth-of-Focus Intraocular Lens in Patients with Cataract: A Prospective Clinical Trial

Purpose

To investigate visual performances after a unilateral or bilateral implantation of enlarged depth-of-focus intraocular lens in patients with cataract.

Methods

In this prospective study, uneventful phacoemulsification and TECNIS® Symfony intraocular lens implantation were performed in 20 eyes of 17 patients. At postoperative 1, 4, and 12 weeks, the logarithm of the minimal angle of resolution visual acuity at far, intermediate, and near distances and the spherical equivalent in manifest refraction and automated refraction were measured. A questionnaire was used to investigate glare, spectacle dependency, and satisfaction at 12 weeks. The mean numerical error and mean absolute error were compared between intraocular lens formulas to assess the best-fit formula.

Results

The logarithm of the minimal angle of resolution visual acuity significantly improved to 0.02 at far, 0.02 at intermediate, and 0.27 at near distances at 12 weeks (p < 0.05). Spherical equivalent was −0.79 D on automated refraction and was significantly lower than −0.26 D measured on manifest refraction. Patients' satisfaction score was 9.06, 8.94, and 6.65 for far, intermediate, and near distances, respectively. Near glasses were required in 5 patients and 2 patients complained of photic phenomenon. Visual performances were not significantly different between bilateral and unilateral implanted patients. No patients reported bilateral imbalance due to unilateral surgery. The mean numerical error was closest to 0 D using the Barrett Universal II formula. The mean absolute error was not significantly different between these formulas.

Conclusion

Unilateral or bilateral implantation of the enlarged depth-of-focus intraocular lens seems to be equally effective in improving visual performances in patients with cataract.

Validity of automated refraction after segmented refractive multifocal intraocular lens implantation

AIM

To evaluate the clinical utility of automated refraction (AR) and keratometry (KR) compared with subjective or manifest refraction (MR) after cataract or refractive lens exchange surgery with implantation of Lentis Mplus X (Oculentis GmbH) refractive multifocal intraocular lens (IOL).

METHODS

Eighty-six eyes implanted with the Lentis Mplus X multifocal IOL were included. MR was performed in all patients followed by three consecutive AR measurements using the Topcon KR-8000 autorefractor. Assessment of repeatability of consecutive AR before and after dilation with phenylephrine 10%, and comparison of the AR and KR with MR using vector analysis were performed at 3mo follow-up.

RESULTS

Analysis showed excellent repeatability of the AR measurements. Linear regression of AR versus MR showed good correlation for sphere and spherical equivalent, whereas the correlation for astigmatism was low. The mean difference AR-MR was -1.28±0.29 diopters (D) for sphere. Astigmatism showed better correlation between KR and MR.

CONCLUSION

We suggest AR sphere plus 1.25 D and the KR cylinder as the starting point for MR in eyes with a Lentis Mplus X multifocal IOL. If AR measurements are equal to MR, decentration of the IOL should be suspected.

Outcomes of excimer laser enhancements in pseudophakic patients with multifocal intraocular lens

Purpose

The aim of this study was to assess visual and refractive outcomes of laser vision correction (LVC) to correct residual refraction after multifocal intraocular lens (IOL) implantation.

Patients and methods

In this retrospective study, 782 eyes that underwent LVC to correct unintended ametropia after multifocal IOL implantation were evaluated. Of all multifocal lenses implanted during primary procedure, 98.7% were refractive and 1.3% had a diffractive design. All eyes were treated with VISX STAR S4 IR excimer laser using a convectional ablation profile. Refractive outcomes, visual acuities, patient satisfaction, and quality of life were evaluated at the last available visit.

Results

The mean time between enhancement and last visit was 6.3±4.4 months. Manifest spherical equivalent changed from −0.02±0.83 D (−3.38 D to +2.25 D) pre-enhancement to 0.00±0.34 D (−1.38 D to +1.25 D) post-enhancement. At the last follow-up, the percentage of eyes within 0.50 D and 1.00 D of emmetropia was 90.4% and 99.5%, respectively. Of all eyes, 74.9% achieved monocular uncorrected distance visual acuity 20/20 or better. The mean corrected distance visual acuity remained the same before (−0.04±0.06 logMAR [logarithm of the minimum angle of resolution]) and after LVC procedure (−0.04±0.07 logMAR; P=0.70). There was a slight improvement in visual phenomena (starburst, halo, glare, ghosting/double vision) following the enhancement. No sight-threatening complications related to LVC occurred in this study.

Conclusion

LVC in pseudophakic patients with multifocal IOL was safe, effective, and predictable in a large cohort of patients.

Retinal Image Simulation of Subjective Refraction Techniques

Refraction techniques make it possible to determine the most appropriate sphero-cylindrical lens prescription to achieve the best possible visual quality. Among these techniques, subjective refraction (i.e., patient's response-guided refraction) is the most commonly used approach. In this context, this paper's main goal is to present a simulation software that implements in a virtual manner various subjective-refraction techniques--including Jackson's Cross-Cylinder test (JCC)--relying all on the observation of computer-generated retinal images. This software has also been used to evaluate visual quality when the JCC test is performed in multifocal-contact-lens wearers. The results reveal this software's usefulness to simulate the retinal image quality that a particular visual compensation provides. Moreover, it can help to gain a deeper insight and to improve existing refraction techniques and it can be used for simulated training.

Autorefraction versus subjective refraction in a radially asymmetric multifocal intraocular lens

PURPOSE

To evaluate whether the automated refraction (AR) correlates with subjective manifest (MR) refraction in eyes implanted with radially asymmetric multifocal intraocular lens (IOLs).

METHODS

This retrospective study evaluated 52 eyes (52 patients) implanted with a radially asymmetric multifocal IOL (LS-312 MF30, Oculentis, Germany). At 3 months postoperatively, the AR and MR values were compared to determine the correlation between the sphere (S), the spherical equivalent (SE) and the astigmatic components J0 and J45.

RESULTS

The difference of mean spherical measurement was +0.98D ± 0.62, with the AR measuring more myopic. The difference of the mean spherical equivalent was +1.11D ± 0.57, again with AR being more myopic. Both these differences were statistically significant (p < 0.001). The astigmatic components showed less differences, with the mean difference of the J0 being -0.09D ± 0.43, and the J45 of +0.04D ± 0.47, which were both not statistically significant (p = 0.123 and p = 0.531, respectively). Correlation analysis of the refractive parameters showed r(2) = 0.067, r(2) = 0.078, r(2) = 0.018 and r(2) = 0.015, respectively, all of which point to a low correlation between the AR and the MR.

CONCLUSION

Autorefraction shows poor correlation to manifest subjective refraction with these radially asymmetric multifocal IOLs. The autorefraction systematically underestimates the spherical and spherical equivalent power, while the correlation between the astigmatic components was also low. Autorefraction seems not a valid starting point for manifest subjective refraction with these types of lenses, unless a corrective factor of about +1 dioptre is used.

Comparison of visual performance of multifocal intraocular lenses with same material monofocal intraocular lenses

Purpose

To compare the visual performance of multifocal intraocular lenses (IOLs) and monofocal IOLs made of the same material.

Methods

The subjects included patients implanted with either Tecnis® monofocal IOLs (ZA9003 or ZCB00) or Tecnis® multifocal IOLs (ZMA00 or ZMB00) bilaterally. We conducted a retrospective study comparing the two types of IOLs. The multifocal group included 46 patients who were implanted with Tecnis® multifocal IOLs bilaterally. The monofocal group was an age- and sex-matched control group, and included 85 patients who were implanted with Tecnis® monofocal IOLs bilaterally. Lens opacity grading, the radius of corneal curvature, corneal astigmatism, axial length and the refractive status were measured preoperatively. Pupil size, ocular aberrometry, distance, intermediate and near visual acuity, contrast sensitivity with and without glare and the responses to a quality-of-vision questionnaire were evaluated pre- and postoperatively.

Results

The uncorrected near visual acuity was significantly better in the multifocal group, whereas both the corrected intermediate and near visual acuity were better in the monofocal group. Contrast sensitivity (with and without glare) was significantly better in the monofocal group. The rate of spectacle dependency was significantly lower in the multifocal group. There were no significant differences between the two groups regarding most items of the postoperative quality-of-vision questionnaire (VFQ-25), with the exception that the patients in the monofocal group reported fewer problems with nighttime driving.

Conclusions

The multifocal IOLs used in this study reduced spectacle dependency more so than monofocal IOLs and did not compromise the subjective visual function, with the exception of nighttime driving.

Toward zero effective phacoemulsification time using femtosecond laser pretreatment

OBJECTIVE

To compare effective phacoemulsification time after femtosecond laser pretreatment with conventional phacoemulsification and the associated effect on visual outcomes and endothelial cell loss.

DESIGN

Prospective, consecutive, single-surgeon case-control study.

CONTROLS

Controls underwent phacoemulsification cataract extraction plus insertion of an intraocular lens (IOL). Cases underwent pretreatment with the femtosecond laser followed by phacoemulsification cataract extraction and IOL insertion.

METHODS

Two hundred one eyes underwent cataract surgery between April 2012 and July 2012. Data collected included patient demographics, preoperative characteristics, femtosecond lens fragmentation method, effective phacoemulsification time (EPT), intraoperative complications, and postoperative outcomes.

MAIN OUTCOME MEASURES

Effective phacoemulsification time, intraoperative complications, corneal endothelial cell loss, as well as postoperative best-corrected visual acuity, intraocular pressure, and refractive outcomes.

RESULTS

Patient demographics were similar between groups. There was no difference between baseline cataract grades (2.59 ± 0.71 vs. 2.52 ± 0.72, not significant). One hundred percent of cases pretreated with the femtosecond laser had complete capsulotomy. Mean EPT was reduced by 83.6% in the femtosecond pretreatment group (P<0.0001) when compared with controls, with 30% having 0 EPT (P<0.0001). Effective phacoemulsification time was reduced 28.6% within the femtosecond group using improved lens fragmentation algorithms, and a further 72.8% reduction was achieved with a 20-gauge phacoemulsification tip. Overall, there was a 96.2% reduction in EPT between controls and the optimized femtosecond pretreatment group. This was associated with a 36.1% reduction in endothelial cell loss in the femtosecond group. Visual and refractive outcomes were similar to those of conventional cataract surgery.

CONCLUSIONS

Femtosecond laser pretreatment results in a significant reduction in effective phacoemulsification time, including the possibility of 0 EPT. Further reductions may be achieved using optimization of lens fragmentation patterns and surgical technique.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Pseudophakic monovision using monofocal and multifocal intraocular lenses: hybrid monovision

PURPOSE

To evaluate the visual function after bilateral cataract surgery performed with a new technique (hybrid monovision) that uses a monofocal intraocular lens (IOL) and a diffractive multifocal IOL.

SETTING

Department of Ophthalmology, Kitasato University Hospital, Kanagawa, Japan.

DESIGN

Case series.

METHODS

Hybrid monovision was achieved by implanting a monofocal IOL (AQ310Ai) in the dominant eye and a diffractive multifocal IOL (Tecnis ZM900) in the nondominant contralateral eye. The target refraction was emmetropia in both eyes. Visual acuity at various distances, contrast sensitivity, near stereopsis, reading ability, and the degree of patient satisfaction were measured.

RESULTS

The study enrolled 32 patients with a mean age of 61.2 years ± 14.7 (SD). At all distances, the mean binocular visual acuity was better than 0.1 logMAR. Binocular contrast sensitivity was better than monocular vision in the eye with the diffractive multifocal IOL. Near stereopsis within normal range was maintained in 62.5% of patients. Of the patients, 18.8% reported spectacle dependence. With binocular vision, no patients reported waxy vision (ie, as though they were looking through water).

CONCLUSION

Hybrid monovision may be an effective approach for managing loss of accommodation after cataract surgery and may be the method of choice in cases of waxy vision caused by bilateral multifocal IOL implantation.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

LASIK outcomes following multifocal and monofocal intraocular lens implantation

PURPOSE

To evaluate the efficacy, predictability, and safety of LASIK to correct residual refractive error following cataract surgery using multifocal and monofocal intraocular lenses (IOL).

METHODS

Included in this retrospective, comparative study were 100 consecutive eyes with residual refractive error that had undergone cataract surgery with monofocal or multifocal IOL implantation. Two groups were studied according to the implanted IOL--multifocal group (50 eyes, mean age 57.8 +/- 9.9 years) and monofocal group (50 eyes, mean age 51.0 +/- 10.0 years). In all cases, LASLK was performed using the SCHWIND ESIRIS excimer laser.

RESULTS

A statistically significant improvement was observed in uncorrected distance (P < .01) and corrected distance (P < .01) visual acuity at 6 months postoperatively in both groups. A statistically significant reduction was also observed in defocus equivalent and cylinder (P < .01) postoperatively. No statistically significant differences in the percentage of eyes losing lines of corrected distance visual acuity were found between groups (14% multifocal vs 4% monofocal, P = .40). When comparing eyes undergoing hyperopic LASIK in each group, a difference in the limit of statistical significance was found in the percentage of eyes with a spherical equivalent refraction within +/- 0.50 diopters (70% multifocal vs 84% monofocal, P = .06). No significant differences in predictability were found between multifocal and monofocal myopic subgroups (P = .25).

CONCLUSIONS

Laser in situ keratomileusis refinement after cataract surgery with monofocal IOL implantation provides a more accurate refractive outcome than after multifocal IOL implantation. Predictability of LASIK correction is limited in hyperopic eyes implanted with multifocal IOLs.

Prevention of Hyperopic Surprise after LASIK in Patients with Refractive Multifocal Intraocular Lenses

Purpose.

Three cases of patients who developed a similar hyperopic defect in refraction following laser in situ keratomileusis (LASIK) after multifocal intraocular lens (IOL) implantation are described.

Methods.

Ophthalmologic evaluation including refractive status, corrected and uncorrected visual acuity (both at far and near), and corneal topography in patients presenting similar hyperopic refractive surprise in one eye as a result of LASIK refinement of residual ametropia after refractive multifocal IOL implantation.

Results.

Laser in situ keratomileusis enhancement for residual ametropia of −1.00 to −1.50 D in patients with a prior implantation of refractive multifocal IOL resulted in a refractive surprise of +2.25 to +2.50 D. After excluding other possible sources of error, an explanation for such a refractive surprise is suggested, and a simple method for avoiding this error is presented.

Conclusions.

Proper knowledge of the defocus curve and the use of a systematic method for determining subjective refraction in patients implanted with refractive multifocal IOLs will reduce the possibility of refractive surprise after LASIK enhancement in a bioptics procedure.